1. Field of the Invention
This invention relates to a fusion thermal transfer recording sheet, particularly to a thermal transfer recording sheet excellent in low-density dot reproduction performance and ink luster of printed graphics.
2. Description of the Background Art
As a thermal transfer recording sheet exhibiting good oil absorptivity, Japanese Patent Application Publication No. 5-78439 teaches a sheet having an ink-receiving layer composed mainly of a water-soluble high polymer and a porous pigment such as calcined kaolin.
On the other hand, Japanese Patent Application Laid-open No. 62-278088 teaches a thermal transfer recording sheet having an ink-receiving layer composed mainly on an inorganic pigment such as calcined kaolin and a high polymer adhesive formed on a biaxial oriented film.
The sheet using water soluble high polymer has inferior ink compatibility and is poor in printability owing to its low affinity for the ink.
The sheet using biaxial oriented film is required to have its ink-receiving layer made 20-50 .mu.m thick in order to block heat that would otherwise cause thermal curling at the time of pressure contact with the thermal head.
Unlike these earlier technologies, the present invention provides a thermal transfer recording sheet that uses a hydrophobic binder resin, can have its ink-receiving layer reduced to a thickness between 1 .mu.m and less than 20 .mu.m, is excellent in low-density dot reproduction performance, is excellent ink luster of printed graphics, and exhibits high optical density at maximum energy.